In vivo studies of HSV-1 latency and reactivation in mice are essential for the successful completion of this Program Project. The studies of HSV-1 latency and reactivation proposed involving Hsd:ICR mice will be conducted in one of two animal facilities in the Harvard Medical Area: the new BSL2/3 facility in the old Channing Laboratory on Longwood Avenue (Projects 5 and 6) or the Beth Israel Deaconess animal facility in the Research North Building on Brookline Avenue (Projects 4 and 7). All studies involving Balb/C mice (Project 1) will be carried out in the Longwood Avenue facility. Although transgenic mice will be utilized in Projects 5, 6 and 7, the special expertise, procedures and oversight needed to generate and maintain these mouse strains necessitates their being housed in, and administered as a separate facility. M. Greenberg will direct Core B, the Transgenic Mouse Facility, at Children's Hospital. When mice generated as part of Core B are inoculated with virus the procedures described here will be used. A description of the mouse strain to be used in the Transgenic Facility can be found in the description of Core B. The Core A Mouse Facility will be directed by P. Schaffer who will oversee studies conducted at both the Longwood and Brookline Avenue facilities. She will train personnel in all four participating labs in proper mouse inoculation, handling and euthanasia procedures as well as TG removal and TG cell culture techniques. Financial oversight of Core A will be the responsibility of the Research Coordinator in the Schaffer lab (Project 4).